Under President Trump, U.S. soft power has been weakened, critics say. And according to Douglas E. Lute, a former ambassador to NATO, “Trump has made it harder, not easier, to follow the U.S. lead.” (The Minnesota Star Tribune)

It will not shock readers that I'm not the biggest fan of the Trump administration's foreign policy stylings. The secretary of state's performance has been embarrassing. The president's decision to withdraw from the Paris climate change accord was so bad it caused me to laugh in disbelief at this administration's grand strategy, which I have decided to label as "clown-car realism."

All of this was before the terrorist incidents in London, in which Donald Trump beclowned himself so badly online that State Department officials vented to BuzzFeed in frustration.

But if you think I've been pessimistic, that's nothing. Last week caused the Financial Times' Martin Wolf to write, "This still looks like the end of the U.S.-led world order," and CNN foreign-affairs host Fareed Zakaria to say, "This will be the day that the United States resigned as the leader of the free world."

This intense worrying, in turn, has triggered some pushback by conservatives who are decidedly not clowns. They may not love Trump, but they argue that American power and leadership have not changed all that much.

Consider two recent essays in the National Review. Senior writer David French argues that none of Trump's contretemps alters the fundamental realities of the U.S. relationship with allies:

"Decades of national choices have left Trump's political opponents with no real option other than feeble protest and symbolic gestures. America is indispensable to the national security of every single one of its allies. America is arguably even indispensable to the economy of every single one of its allies. So long as America remains in NATO, keeps its treaty obligations elsewhere, and maintains its economic strength, it is and will be the leader of the free world, and the world's dominant global power."

Senior writer Michael Brendan Dougherty goes further, concluding that four months of Trump haven't fundamentally altered the distribution of power in the world:

"There is a frantic, almost panicked desire to see dramatic declines in U.S. power and prestige because its people elected Donald Trump. The people have to learn their lesson, after all. But the reality-based community has lost touch with the real world. America remains a hegemonic force: It has the largest and best equipped military that secures peace and prosperity from Europe to the South China Sea, the most prestigious university system, the largest consumer market, and it remains the source of so much innovation."

These arguments have their merits. The United States remains the most powerful actor in world politics. And I don't think the economic or military foundations of American power have changed so significantly from, say, a year ago, when the United States seemed in a pretty good position.

From a hard-power perspective, the United States is still in decent shape, although China is catching up.

The problem is twofold. First, there are other components of power beyond guns and butter. Second, leadership in world politics is about power and purpose. The Trump administration has been derelict or worse on the latter.

On the power dimension, soft power matters as well as hard power. Trying to get other actors to want the same things you want is a useful trait, and I fear that the Trump administration's God-awful messaging guarantees that won't happen.

Realists might argue that such concepts are mushy, but there's evidence that Trump's blunders will complicate the next steps in Afghanistan. The Pentagon is proposing that U.S. allies shoulder an increased fraction of the troops in that country. But the New York Times reported June 3:

"That proposal depends on nailing down commitments from NATO and other allies — a task that former officials said had gotten harder after Mr. Trump's stormy visit to Europe, where he chided allies for not paying their fair share of the alliance's upkeep and declined to reaffirm America's commitment to mutual defense.

" 'Trump has made it harder, not easier, to follow the U.S. lead,' said Douglas E. Lute, a former ambassador to NATO who advised both ... Obama and ... George W. Bush on Afghanistan. 'Questioning U.S. leadership makes it more difficult for the allies to send troops into harm's way.' "

Withdrawing from the Paris accord further weakens U.S. soft power, as Meghan O'Sullivan, an official in the George W. Bush administration, pointed out in Bloomberg News last week. Dougherty suggests that America remains an attractor for others because of our university system, but that can erode quickly under Trump.

Will this matter if, say, Russia decided to invade Poland, or North Korea decided to attack South Korea? No. Those are areas where hard power matters a great deal. If, however, the United States wants to create anything new, or try to tweak the status quo across a wide array of issues, then cajoling allies and partners to join has become that much harder under Trump.

The other problem with the Trump administration is that it has manifestly refused to articulate a common social purpose to attract other countries. Say what you will about Bush, his second inaugural address put forward an appealing vision. Obama was less bold but no less certain about the utility of liberal internationalism.

By definition, Trump's strategy of "America first" is of little appeal to non-Americans. In his inaugural address, Trump stated: "We must protect our borders from the ravages of other countries making our products, stealing our companies and destroying our jobs. Protection will lead to great prosperity and strength." Other countries will not rally behind that message.

Is there any purpose that the Trump administration has promoted that will appeal to others? Vigorous counterterrorism will appeal to some countries, particularly in the Sunni Middle East. "Not lecturing" others about their human rights issues is likely to please some authoritarian countries, particularly in the Sunni Middle East. Traditional U.S. allies in Europe, the Pacific Rim and Latin America will find nothing in these speeches to like, however. That's a very large part of the globe.

It is possible for French, Dougherty, Wolf and Zakaria all to be correct. American power remains formidable, but American leadership is limited in its ability to do much in the Trump era. The United States in 2017 has some power but little purpose. The effect is the same as driving a car without making any investments in upkeep or insurance. Eventually, the car runs afoul of an accident or it breaks down of its own accord.

As other countries view the United States through a more realpolitik lens, this will inevitably create feedback loops that lead to more Hobbesian outcomes. The center of gravity for American leadership will not hold.

Daniel W. Drezner is a professor of international politics in the Fletcher School of Law and Diplomacy at Tufts University. He wrote this article for the Washington Post.